Apparatus for making rotors



April 19 1966 P APPARATUS FOR MAKING ROTORS Original Filed Feb. 20, 1962INVENTOR HANS PFAU iR-LJ A TTORNE Y8. v

United States Patent 3,246,389 APPARATUS-FOR MAKING ROTORS Hans Pfau,Duisburg, Germany, assignor to Demag Aktiengesellschaft, Duisburg,Germany Original application Feb. 20, 1962, Ser. No. 174,621. Dividedand this application June 3, 1964, Ser. No.

1 Claim. (Cl. 29-200) This application is a division of application,Serial No. 174,621, filed February 20, 1962, for Process and Apparatusfor Making Rotors.

This invention relates, in general, to rotor constructions and to amethod of forming a rotor, and in particular to a new and useful rotorconstruction for an axial flow turbine compressor and similar device,and to a method of forming such rotor.

In the manufacture of rotors for axial turbines and axial compressors,it is essential that extreme care be taken to insure the stability andstrength of the rotors which are formed. The requirements with regard tostrength and stability are particularly diflicult to meet in respect tothe securing of the lower portions or feet of the rotors.

Prior to the present invention, it has been established that thegreatest stability is obtained in a rotor construction where the vanesand the hub consist of a single piece. However, the manufacture of sucha rotor in a single piece is very difficult.

In accordance with the present invention, an improved rotor constructionis provided by a process in which the vanes are joined togetherindividually one after the other and welded at their feet along linesextending parallel to the axis or on a coaxial cylinder surface of therotor. To accomplish this, an apparatus is provided to mount one of thevanes on a rotary member having indications thereon corresponding to thenumber of vanes which will eventually be formed into the rotor. Anadditional vane is then mounted in a clamping member and the two arebrought together so that the feet align on each side. Thereafter,welding is accomplished along the juncture between feet in a directionparallel to the axis or on a coaxial surface of the rotor to be formed.Additional vanes are connected one at a time in the same manner. Whenall of the vanes have been welded together, a vane ring is formed by theconnections of the rotor feet. The vane ring is subsequently connectedwith a hub body by means of one or more annular welding seams made toconnect the hub body to the vane ring.

The process is advantageously carried out using the apparatus bysecuring a first vane or a complete segment of vanes to the rotatablearm in such a manner that the vanes which have been connected togethermay be swung through an arc to align with the next vane which ispositioned in a stationary clamping member. *An advantage of the methodis that each vane, as it is welded to the other vanes in the alreadyformed segment, is relieved from the clamping device so that no internalpressures will be built up and it will be permitted to freely expand andcool.

The process proposed in the present invention prevents the occurrence ofpartial joints between the individual vane feet which may be apt tocause localized stress areas which may fail. This results in a veryconsiderable advantage providing a vane ring which is capable ofabsorbing tangential stresses and tensions and the danger of radialcrevice or cleavage formation during the production of the annular seamis entirely prevented.

With such a process, it is possible to use all types of materials whichare capable of being Welded. The finished rotor does not contain anyjoints and therefore, for practical purposes, it is in an ideal statesimilar to a rotor "ice which has been made from a single piece. Inaddition, it is possible, in accordance with the inventive process, tomake a precise division between the individual vanes of the overallrotor construction.

Accordingly, it is an object of this invention to provide an improvedprocess for manufacturing a rotor.

A further object of the invention is to provide an improved device forfacilitating the manufacture of rotors.

A further object of the invention is to provide an improved process formanufacturing a rotor for an axial compressor, turbine and the like,comprising joining together individual blades of the rotor one after theother at their feet by welding along lines substantially parallel to theaxis or on a coaxial cylinder surface of the rotor which will eventuallybe formed and thereafter joining the ring of blades thus formed to acentral body member by welding. A further object of the invention is toprovide a rotor construction which includes a plurality of individualrotor blades having foot portions which are joined together alongwelding seams extending substantially parallel to the axis or on acoaxial cylinder surface of the formed rotor and includes a central hubbody which is joined to the ring of rotor blades by welding.

A further object of the invention is to provide an apparatus for weldingindividual blades of a rotor together to form a complete rotor ringstructure including a rotatable arm, an indicator ring havinggraduations thereon corresponding to the number of vanes formed in therotor, clamping means on the arm for clamping a blade or a segmentcomprising a plurality of blades thereon and means for clamping anindividual rotor blade adjacent the rotatable arm for joining eachindividual blade in succession to form an overall rotor ring.

A further object of the invention is to provide an improved process formanufacturing a rotor which is simple to execute, economical to carryout and produces an improved rotor structure. The various features ofnovelty which characterize the invention are pointed out withparticularity in the claims annexed to and forming a part of thisspecification. For a better understanding of the invention, itsoperating advantages and specific objects attained by its use, referenceshould be had to the accompanying drawings and descriptive matter inwhich there is illustrated and described a preferred embodiment of theinvention.

In the drawings:

FIG. 1 is a perspective view of an individual rotor vane constructed inaccordance with the invention;

FIG. 2 is a perspective view indicating the joining together of twovanes by welding;

FIG. 3 indicates an apparatus for holding two rotor blade elementstogether for joining together by welding constructed in accordance withthe invention;

FIG. 4 is a view of the apparatus of FIG. 1 indicating a segment held bythe apparatus for joining to gether of an additional vane thereto; and

FIG. 5 is a transverse section of a rotor constructed in accordance withthe invention.

Referring to the drawings in particular, the invention embodied thereinas indicated in FIG. 1 includes a rotor which is made up of a pluralityof blades or vanes generally designated 1 which includes a blade portion1a and a foot portion 112. The foot portion is elongated in an axialdirection in respect to the overall rotor which will be formed andincludes curved sides 10, 1c which form fillers to receive a weld inaccordance with the invention.

In accordance with the invention, a ring formed of rotor blades is madeby placing two of the rotor blades 1 together as indicated in FIG. 2with an axial elongated edge 10 of one abutting an axially elongatededge 12 of the other. In this position, they are welded together in ajointless manner by welding as indicated at 2 to completely fill thespace formed between the curved portions 10, 1c of adjacent vanes 1. Asindicated in FIG. 3, the preferred apparatus for carrying out apreferred form of the method is indi-' cated. The apparatus includes anindicating ring generally designated 7 upon which is rotatably mountedon a pin 6 a rotating clamping arm 5. The clamping arm is initiallyprovided with a holding piece element 4 which is bolted thereto by meansof a bolt 14. To effect the formation of the rotor wheel, a first rotorelement 3 is welded to the piece 4 which is secured on the end of therotatable arm 5. A second rotor blade element 8 is then clamped in aclamping device 9 and the arm 5 is rotated to cause the blade element 3to be positioned with its elongated axial edge 12 adjacent the elongatedaxial edge of the blade element 8. When this is done means on theopposite side of the indicator disc (not shown) are provided to securethe pin 6 against turning in order to lock the arm 5 in its alignedposition. Thereafter, the blade elements 3 and 8 are joined together bya welding seam made between opposing side faces 10, 1c of the footportions along a line extending substantially parallel to the axis ofthe rotor which will be formed.

After a full quarter segment of the rotor is formed by joining togethera plurality of the vane element in the manner described above, acomplete quarter segment is mounted on the arm 5 by suitable clampingmeans (not shown) after piece 4 is first removed. Additional vanes areadded to the segment 14 until a complete ring is formed by joiningtogether all the vane feet. During the manufacture of the completerotor, care has to be taken that each vane is exactly positioned in theproper alignment with the segment which has already been formed. Theapparatus which includes the rotatable arm insures that accuratealignment will be accomplished. In order to insure that the segment 15is accurately positioned on the arm 5, the arm 5 is first rotated up tothe mounting position of the first and then rotated to the mountingposition of the last vane. The indicated disc 7 is then adjusted withregard to the division between the vanes and the welding of all theadditional vanes is then set by positioning the arm 5 in relation to theindicated disc 7. i

In the process of the invention, it is possible to insure that the samerelative position in relation to the center of the rotor which is to beformed is achieved for each of the vane elements. Thus, any inaccuraciesor form changes which may occur during the welding of each individualvane element will not be additive. Thus, upon securing of a new vane inposition, any displacement or misalignment which has occurred during thepreceding welding which may be due, for example, to shrinking or stressrelieving due to temperature changes or the like is automaticallyreconsidered by the accurate positioning of the arm 5 so that anabsolute uniform vane ring is formed. An important step in the processis that each vane element, after it is welded to the segment, isreleased from its clamping member and permitted to expand and cool sothat no stresses are locked into the rotor which is formed. Bypermitting each vane element to freely expand after it has been welded,the resultant rotor will be free of any tensions or stresses which maycause failure during its operation.

After a complete ring of vane elements is formed, it is placed around ahub member or body 13 as indicated in FIG. 5 and the two structures arewelded together by making annular welding seams at the location 20 ofFIG. 5.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventionprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

An apparatus for welding individual blades of a rotor together to form acomplete rotor ring structure, including a stationary blade clamp, anarm rotatably mounted adjacent said clamp including means to hold atleast one blade thereon, and a disc mounted concentrically with said armhaving indications thereon at angularly spaced locations equal to thenumber of blades in the rotor.

References Cited by the Examiner UNITED STATES PATENTS 2,448,825 9/1944Price et al. 253-77 WHITMORE A. WILTZ, Primary Examiner.

CHARLES W. LANHAM, Examiner.

